Cooled polymer component

ABSTRACT

A polymer airfoil assembly is disclosed and includes at least one cooling passage for circulating coolant to remove heat from the polymer airfoil portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/838,668 filed Dec. 12, 2017.

BACKGROUND

Most components in a gas turbine engine are exposed to extremetemperatures and pressures that dictate the use of high temperaturecompatible materials such as metals and ceramics. Moreover, even withthe use of high temperature compatible materials, additional coolingfeatures are needed to provide desired performance and durability. Somesystems are exposed to lower temperatures and still use metals that arewell within acceptable working temperatures. Polymer materials do nothave high working temperatures as compared to metals and ceramics.However, polymer materials are easily formed and less costly incomparison to metals and ceramic materials.

SUMMARY

A polymer airfoil assembly according to an exemplary embodiment of thisdisclosure, includes among other possible things a polymer airfoilportion and at least one cooling passage within the polymer airfoilportion for circulating a coolant to remove heat from the polymerairfoil portion.

A component for a system of a gas turbine engine according to anotherexemplary embodiment of this disclosure, includes among other possiblethings a body portion formed from a polymer material and at least onecooling passage configured to allow coolant to pass therethrough toenable the component to operate while exposed to temperatures in excessof a predefined temperature range of the polymer material.

A method of forming a body portion of a component for a gas turbineengine according to another exemplary embodiment of this disclosure,includes among other possible things forming the body portion from apolymer material and forming at least one cooling passage within thebody portion configured to allow coolant to flow therethrough.

Although the different examples have the specific components shown inthe illustrations, embodiments of this invention are not limited tothose particular combinations. It is possible to use some of thecomponents or features from one of the examples in combination withfeatures or components from another one of the examples.

These and other features disclosed herein can be best understood fromthe following specification and drawings, the following of which is abrief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example gas turbine engine.

FIG. 2 is a schematic view of an example polymer airfoil embodiment.

FIG. 3 is a cross-sectional through an example polymer airfoilembodiment.

FIG. 4 is a schematic view of a portion of an example polymer airfoilembodiment.

FIG. 5 is a cross-sectional view of a portion of an example polymerairfoil embodiment.

FIG. 6 is another cross-sectional view of another example polymerairfoil embodiment.

FIG. 7 is a cross-sectional view of a portion of another polymer airfoilembodiment.

FIG. 8 is a schematic view of a cross-section of example group ofcoolant passages.

FIG. 9 is a cross-section of another group of example coolant passages.

FIG. 10 is a schematic view of yet another group of example coolantpassages.

FIG. 11 is a cross-sectional view of another example polymer airfoilembodiment.

FIG. 12 is a schematic view of an example method of fabricating apolymer airfoil.

DETAILED DESCRIPTION

Referring to FIG. 1, an example gas turbine engine 10 is schematicallyshown and includes a fan 12, a compressor 14, a combustor 16 and aturbine 18 all disposed along a common longitudinal engine axis A. Airis compressed in the compressor 14, communicated to the combustor 16,mixed with fuel and ignited to generate a high energy exhaust flow thatis expanded through the turbine 18. The turbine 18 converts the highenergy exhaust flow to mechanical energy to drive the fan 12 andcompressor 14. Each of the compressor 14 and turbine 18 include airfoils22, 24, respectively. The airfoils 22, 24 are either part of a rotatingblade or a fixed vane and both are within the contemplation of thisdisclosure. The turbine 18 may also include blade outer air seals 32that are disposed proximate to tips of the airfoils 24 to maintain adesired clearance. The aforementioned and other components within thegas stream are exposed to high working temperatures.

The example gas turbine engine 10 also includes an environmental controlsystem 20 that draws air from a portion of the compressor 14 andutilizes that air for use in other system schematically shown at 30 forcooling airflow or for cooling of an aircraft cabin. Some environmentalcontrol systems 20 include a turbo compressor 28 that also may includeairfoils 26 within compressor and turbine sections. Moreover, althoughthe disclosed example illustrates air drawn from the engine, air for thecabin may draw air from the atmosphere, an engine bypass flow path orother sources.

Polymer materials have a very low working temperature capability ascompared to the materials currently utilized in sections exposed to hightemperatures. However, some sections of the engine or system may operatewithin a temperature range just outside working ranges of known polymermaterials.

Referring to FIG. 2 with continued reference to FIG. 1, an exampleairfoil 34 is illustrated and is formed from a polymer material. Polymermaterials provide easier manufacturability as they may be formedutilizing common insert molding or other molding processes. The examplepolymer airfoil 34 includes a leading edge 36, a trailing edge 38 and anairfoil portion 44 that extends from a platform 40 to a tip 42. Itshould be understood that although the example airfoil 34 is shown as ablade, the contents of this disclosure are applicable to vanes, bladesas well as other components exposed to temperatures just above a workingtemperature range of known polymer materials.

The example polymer airfoil 34 includes cooling air passages 50 thatreceive cooling air from an inlet 46 and exhaust that cooling air out anoutlet 48. The use of cooling passages within the polymer airfoil 34maintains a temperature of the airfoil 34 within acceptable ranges ofthe airfoil 34 making it applicable for use in various systems andlocations within a gas turbine engine that would not otherwise besuitable for polymer materials.

Polymer materials have a lower thermal conductivity and thereforecoolant fed through cooling passages 50 absorbs less heat as compared tometal or ceramic materials. The reduced thermal conductivity of thepolymer materials enables the cooling passages to be longer as coolantwithin the cooling passages does not heat up as quickly compared tocoolant within a part made from a more thermally conductive material.Moreover, the example cooling passages 50 are much closer to an outersurface of the airfoil 34 to accommodate the lower thermal conductivity.The cooling passages 50 may communicate airflow to cooling holes 52 togenerate external film cooling along surfaces of the airfoil 34.

Referring to FIG. 3 with continued reference to FIG. 2, the examplepolymer airfoil 34 is shown in cross-section and includes a wall 54including an external surface 56 and an internal surface 58. Theplurality of passages 50 for coolant are schematically shown as formedby corrugations 60 along the inner surface 58 of the airfoil wall 54.The corrugations 60 are provided between an inner wall 75 and the innersurface 58 to provide the passages 50 for cooling airflow proximate tothe inner surface 58 to cool the airfoil surface 56 and improve theworking temperature capability of the polymer material utilized to formthe airfoil 34. The working temperature capability of polymer materialas utilized in this disclosure is that temperature range or upper limitwhere the material properties of the polymer material maintainpredefined structural characteristics for a predefined period. Theairfoil 34 may include internal cavities 62, 64 that feed and collectcooling airflow not exhausted through cooling holes 52.

Referring to FIG. 4 with continued reference to FIG. 3, because thepolymer material has a lower thermal conductivity, the passages 50 maybe of increased length. In this example, it is schematically shown thata first passage 72 is provided that communicates cooling air to a firstportion 68. A second passage 70 is provided that provides coolingairflow to a second portion 66. Because coolant within the coolantpassages 70, 72 does not absorb heat as quickly, longer passages can beutilized to communicate airflow to specific locations within the airfoil34.

In this disclosed example, cooling air is communicated into an airfoil43 through an inlet 45 and exhausted through an outlet 47 that isseparated from the flow over the airfoils surfaces. The example airfoil43 differs from the previous example airfoil 44 by not including filmcooling openings that are in communication with the airflow. In someinstances, the airfoil 43 may be in environment where cooling air withinthe airfoil 43 is a lower pressure than flow on the outside of theairfoil 43. In such an instance, higher pressure external airflows wouldflow into the airfoil 43. Therefore in the disclosed airfoil 43, coolingair inlet and exhausted from the cooling passages 72 and 70 through asurface not in communication with external airflows. The separationenables lower pressures of cooling air to be used within the airfoil 43.

Referring to FIG. 5 with continued reference to FIGS. 2 and 3, theexample airfoil 44 is shown in cross-section with a portion of the wall54. The corrugations 60 are provided between the inner wall 75 andabutted against the inner surface 58 at a thickness 76 from the outersurface 56 of the wall 54. In one example, the thickness 76 isapproximately 1 mm (0.039 inch). In another example, the thickness 76 isbetween 0.5 mm (0.012 inch) and 2 mm (0.079 inch). Moreover, thedisclosed ranges of thicknesses could be modified and therefore otherthickness ranges are within the contemplation of this disclosure. Thereduced thickness 76 of the wall 54 in the portions where thecorrugations 60 enable the coolant to be closer to the surface 56 toimprove conduction of heat into coolant.

Referring to FIG. 6, in another example cooling passage configuration, afirst set of corrugations 74 is shown extending in a first direction anda second set of corrugations 78 is shown in a direction transverse tothe first direction of the first set of corrugations 74. Thecorrugations 74, 78 may be orientated such that passages are 90 degreesfrom each other of at an acute angle no less than about 25 degrees. Thecorrugations 74, 78 provide strength to enable the internal channels tobe extremely close to the external surface 56 to improve thermaltransfer and cooling.

Referring to FIG. 7, in another disclosed example a width 80 along withthe thickness 82 is utilized to provide a dense array of near surfacepassages 78 to aid in heat transfer through the thin layer of polymermaterial. The dense array is provided by having multiple passages withinthe width 80, along with the thickness 82 to accommodate the low thermalconductivity of the materials utilized to form the example airfoils.

In one disclosed example embodiment the density of the cooling passages78 as a ratio passage open area for a given length is between about 0.5and 0.8. As an example the cooling passages 78 may include an open areaof 0.8 inches for each 1.0 inch of width 80 to provide a ratio of 0.8.An open area provided by the cooling passage may be 0.5 inches for each1.0 inch of width providing a ratio of 0.5. As appreciated, other openarea ratios may be utilized and are within the contemplation of thisdisclosure.

The disclosed example airfoil is formed from a polymer material. Itshould be understood that the disclosed and described polymer materialcould comprise any polymer material as is recognized in the artincluding, for example, polyvinyl chloride (PVC), polystyrene,polyethylene, polypropylene, polyacrylonitrile, PVB, silicone,polyeurethane cyanate ester and epoxy along with other know polymerblends. Moreover, other polymer materials as are known in the art thatwould be suitable for formation of an airfoil to provide the desiredstructural rigidity, manufacturability and working temperatureconditions could be utilized and are within contemplation and scope ofthis disclosure.

Referring to FIG. 8, the example corrugations may include a D-shapedcross-section as is illustrated and schematically shown at 84.

Referring to FIG. 9, another cross-sectional shape of the examplepassages is indicated at 86 includes triangle shaped passages that areinverted in alternating pattern. The alternating pattern of trianglesprovide for an increased density of cooling passages near the wall 54 ofthe airfoil.

Referring to FIG. 10, another cross-sectional shape of the coolingpassages shown at 88 includes triangles arranged in a non-invertedmanner.

Referring to FIG. 11, another airfoil embodiment is disclosed andschematically indicated at 122. The airfoil 122 includes internalchambers 124 and 126 that communicate cooling airflow to film coolingopenings 128 distributed throughout the airfoil 122. The low heattransfer properties of the polymer materials are such that internalcooling features may be of only limited cooling efficiency. Accordingly,the cooling method for the example airfoil 122 is provided by film aircooling generated by airflow through the multiple film cooling openings128.

Referring to FIG. 12, an example method of forming the polymer airfoil120 is schematically shown and includes a first process 90 of molding anairfoil 120 as a complete homogenous shape by a single mold 100. In thisexample, a polymer material 112 is injected into the mold 100 that isconfigured to define the shape of the example airfoil 120. It should beunderstood that the mold 100 could be of any configuration understood tobe utilized to performing plastic parts including slides, inserts andother known molding features utilized to form features of the examplepolymer airfoil 120.

Schematically shown at 92 is another process of forming the polymerairfoil 120 and includes the use of an insert 102 of a material not thesame as the polymer material utilized to form the airfoil 120. Theinsert 102 is placed into the mold 100 and over molded with polymermaterial to provide internal features of the completed polymer airfoil120 including a cooling air passage and/or chambers within the airfoil120. In one disclosed example, the insert 102 is of a different polymermaterial than the polymer material utilized to form the outer surfacesof the airfoil. Moreover, the insert 102 may also be of a metal materialor any other materials different from the polymer material utilizedperforming the outer features of the polymer airfoil 120. The insert 102may remain as part of the completed airfoil 120, or be removed to defineinternal features.

Another example process schematically indicated at 94 includes thecreation of the completed polymer airfoil 120 as different separatelymolded components. In the previously disclosed methods of forming thepolymer airfoil the airfoil was formed as a single homogenous part in acompleted shape. In the example process illustrated at 94, several molds104, 106 are utilized to form various pieces 108, 110 that are laterjoined to form a completed polymer airfoil schematically shown at 120.

Another example process schematically indicated at 115 includes additivemanufacturing methods where an airfoil or other component 132 is builtlayer by layer by depositing and melting material from an applicator134. The use of additive manufacturing methods to build a component 132enables formation of intricate internal features schematically shown at136 that may not be feasible or practical utilizing known moldingtechniques.

The disclosed example polymer airfoil includes cooling passages thatenable and accommodate the low thermal conductivity that is acharacteristic of polymer materials. By providing cooling passagesspecifically configured to accommodate the low thermal capacity of thepolymer material, the use of polymer material for applications andenvironments that exceed normal working temperatures become feasible andenable incorporation of polymer materials into various gas turbineengine systems, components and sections.

Although an example embodiment has been disclosed, a worker of ordinaryskill in this art would recognize that certain modifications would comewithin the scope of this disclosure. For that reason, the followingclaims should be studied to determine the scope and content of thisdisclosure.

What is claimed is:
 1. A component for a system of a gas turbine engine,the component comprising: a polymer body portion; and at least onecooling passage within the polymer body portion for circulating acoolant to remove heat from the polymer body portion, wherein a portionof the at least one cooling passage is formed from an insert having adifferent material property than the polymer body portion.
 2. Thecomponent as recited in claim 1, wherein the polymer body portionincludes an outer wall having an external surface and an internalsurface and the at least one cooling passage is disposed along theinternal surface.
 3. The component as recited in claim 2, wherein the atleast one cooling passage comprises a first corrugation orientated in afirst direction within the polymer body portion along the internalsurface.
 4. The component as recited in claim 3, wherein the at leastone cooling passage comprises a second corrugation orientated transverseto the first corrugation along the internal surface.
 5. The component asrecited in claim 2, wherein the at least one cooling passage comprises aplurality of channels having one of a D-shaped cross-section andtriangular-shaped cross-section.
 6. The component as recited in claim 2,wherein that at least one cooling passage comprises a plurality ofchannels having a triangular-shaped cross-section with alternating rowsincluding an inverted triangular-shaped cross-section.
 7. The componentas recited in claim 1, wherein the polymer body portion includes anouter wall having an external surface and an internal surface and the atleast one cooling passage communicates cooling airflow to at least onecooling hole through the outer wall for supplying a flow of cooling airalong the external surface of the polymer body portion.
 8. The componentas recited in claim 1, further comprising a first cavity within thepolymer body portion in fluidic communication with the at least onecooling passage.
 9. The component as recited in claim 8, furthercomprising a second cavity within the polymer body portion and spacedapart from the first cavity, the at least one cooling passage being influidic communication with both the first cavity and the second cavity.10. The component as recited in claim 9, wherein the first cavitysupplies cooling airflow to a cooling passage in a first part of thepolymer body portion and second cavity supplies cooling airflow topassages in a second part of the polymer body portion.
 11. The componentas recited in claim 1, wherein the polymer body portion is formed of apolymer comprising one of a polyvinyl chloride, polystyrene,polyethylene, polypropylene, polyacrylonitrile, silicone, polyurethanecyanate ester and epoxy.
 12. The component as recited in claim 1,wherein the polymer body portion comprises different assembled polymercomponents.
 13. The component as recited in claim 1, wherein thecomponent comprises a shell disposed within one of a compressor sectionand a turbine section of a gas turbine engine.
 14. The component asrecited in claim 1, wherein the component is part of an environmentalcontrol system of a gas turbine engine.
 15. A method of forming a bodyportion of a component for a gas turbine engine comprising: forming thebody portion from a polymer material; and forming at least one coolingpassage within the body portion configured to allow a coolant to flowtherethrough, wherein at least a portion of the at least one coolingpassage is formed from an insert having a different material propertythan the body portion.
 16. The method as recited in claim 15, whereinthe polymer material comprises one of one of a polyvinyl chloride,polystyrene, polyethylene, polypropylene, polyacrylonitrile, silicone,polyurethane cyanate ester and epoxy.
 17. The method as recited in claim15, including forming the body portion as a single homogenous part withthe same polymer material.
 18. The method as recited in claim 15,including forming the body portion from separately molded componentsmade the polymer material.
 19. The method as recited in claim 15,including forming the body portion and the at least one cooling passagewith an additive manufacturing process.